1. Field of the Invention
The present invention relates to a wiring pattern formation method, a manufacturing method for a multi layer wiring substrate, and an electronic device.
Priority is claimed on Japanese Patent Application No. 2004-266646, filed Sep. 14, 2004, the content of which is incorporated herein by reference.
2. Description of Related Art
A starter drive device which drives the starter motor of a vehicle has been, per se, known from the past. Such a starter drive device is an apparatus which supplies electric power to the vehicle starter motor upon the driver actuating a starter switch and turning a starter relay ON. With such a starter drive device, there has been the problem that the starter may be driven uselessly, if the driver of the vehicle continues to actuate the starter switch irregardless of the fact that the starting of the engine has been completed. Furthermore, there has also been the problematical feature that, irrespective of whether the engine has been started, if the driver of the vehicle actuates the starter switch, the starter motor can be driven, so that there is a possibility of a strange sound being generated from the engine, and of possible damage to various components of the starting mechanism.
In this connection, in order to cope with this problem, it has been practiced to provide an electronic control device (ECU) which controls the turning ON and OFF of the starter relay, and which turns the starter relay OFF automatically when the starting of the engine has been completed, and thereafter prohibits the starter relay from being turned ON again during operation of the engine. However, it is necessary to supply a large starting electrical current to the starter motor for starting the engine. Thus, with a starter drive device which employs the above described type of electronic control device, when the power source voltage drops in this manner while driving the starter motor, there is a possibility that the power source voltage which is being supplied to the electronic control device may drop below the necessary minimum voltage for operating its calculation device (CPU), which entails a reset of the calculation device. In this case the driving by the starter motor stops, and as a result there is a possibility that a situation may be arrived at in which it is not possible to start the engine.
Thus, in order to avoid this type of situation, it has been proposed (refer to, for example, Japanese Unexamined Patent Application, First Publication 2003-293916) to provide a normally closed relay which is usually in the state of providing an electrical connection between the starter switch and the starter motor, when no drive electrical current is being provided to the starter relay, while it is in the state of disconnecting the starter switch from the starter motor when a drive electrical current is being provided from the electronic control device to the starter drive relay. With such a starter drive device, if the power source voltage for the electronic control device drops below the operating voltage for its calculation device, since the starter switch and the starter motor are kept in the connected state due to the operation of the normally closed relay even though no current is being provided to the starter relay, it is possible to maintain the supply of operating electrical power to the starter motor, and thus to start the engine.
Furthermore, there has been proposed a starter drive device (refer to, for example, Japanese Unexamined Patent Application, First Publication 2001-132596) in which drive prohibition control of the starter motor is performed, irrespective of whether the starter switch is ON or OFF. Such a starter drive-device is a device which includes a first transistor which changes over between drive permission and drive prohibition for the starter relay, based upon a starter drive permit signal which is outputted from the calculation device, and a second transistor which monitors the state of the calculation device, and which changes over the first transistor between ON and OFF, based upon the state of a pulse type reset signal which is outputted when the calculation device is reset.
However since, with the former above described starter drive device, two power supply systems are required to be connected from a single battery of the vehicle, the cost of the wiring harness and the relays and so on is elevated, as compared with a system in which only one such power supply system is fitted. Furthermore there is a problem in that, even if the power source voltage recovers and reaches the operating voltage of the calculation device, since the calculation device performs its initialization procedure directly after this voltage recovery, the output signal of the calculation device goes to logically indeterminate (high impedance) at this time, and as a result the operation of the starter relay and the normally closed relay becomes unstable.
Moreover, with the latter above described starter drive device, while the reset signal from the calculation device continues during a drop of the power source voltage, the first transistor is switched over so as to prohibit driving of the starter relay, and thereafter, after the input of the reset signal has ceased for a predetermined time period, the first transistor is again switched over so that the starter relay is driven. Due to this, it takes a comparatively long time until the starter relay is driven, and thereby the startability of the engine is undesirably deteriorated. Furthermore since, if the battery has been used for a long time period so that its capacity has deteriorated, there is a possibility that the frequency of such dropping of the power source voltage below the operating voltage of the calculation device when the engine is being started will be increased, and since, when the outputting of the reset signal continues, a considerable time period is taken until the starter relay is driven, accordingly a useless load comes to be imposed upon the battery, and a state may be arrived at in which the engine cannot be started. To describe this situation further, since it is decided that the power source voltage has dropped and the calculation device has run wild merely upon the reset signal being outputted from the calculation device, there is a fear that it may be decided that the power source voltage has dropped, irrespective of whether or not the calculation device is in fact running wild or not, so that and the engine may undesirably be started.